Last season, when they finished 9-7 and won the division for the third time in five years, the Texans played nine games against quarterbacks drafted in the first or second rounds.

In other words, the defense has to be even better than 2015, when the Texans ranked third, including first over the last nine games. Defensive coordinator Romeo Crennel is entering his third season working with coach Bill O'Brien.

"I think every year is different," O'Brien said Tuesday. "I think whatever happened last year has really nothing to do with this year. I really believe that."

O'Brien better hope he's wrong. He needs his defense to duplicate - at least - what it did over the last nine games, when the Texans allowed 263 yards and 12.7 points a game.

"We have to prepare and be ready for the challenges of a new schedule (and) new players we'll be going against," O'Brien said. "We have a lot of players back on our defense, but we'll be seeing some different players on all the teams we're playing."

Like quarterbacks, for instance.

The Texans missed an injured Andrew Luck in both games against Indianapolis last season and beat the Colts on the road for the first time.

They won't be sweeping the Titans and quarterback Zach Mettenberger again. Barring injury, they'll have to defend against Marcus Mariota for the first time.

The last time the Texans played Green Bay, Aaron Rodgers embarrassed them with six touchdown passes. And that was at NRG Stadium. This season, they get Rodgers at Lambeau Field. In December.

The AFC South is the only division the Texans play in which every starting quarterback is a former first-round pick. In 2015, the Texans were 5-1 in the AFC South.

It's going to be hard to duplicate that record if Luck and Mariota remain healthy. Not to mention if Jacksonville's Blake Bortles is improved in his third season.

Last season, the Texans set a franchise record with 45 sacks. Considering the talented quarterbacks they play, this would be a good season to break that record.

"I don't even think about last year when it comes to like, what the stats were," O'Brien said.

O'Brien and his coaches are thinking about ways to avoid another start like last season, when they were 2-5. Four of those defeats were against former first-round picks at quarterback: Kansas City's Alex Smith, Carolina's Cam Newton, Atlanta's Matt Ryan and Miami's Ryan Tannehill.

"One of the things we have to do on both sides of the ball and on special teams is to start better than we did last year," O'Brien said. "We need to start fast."

And he's not just talking about the season. O'Brien is talking about the start of games.

"Yeah, I would say both," he said. "We need to try to do a better job of getting off to a better start in games and definitely a better start in the season."

It would help, of course, if the defense makes life miserable for all those talented quarterbacks who were drafted in the first round.